Conventional compressing diaphragm pumps of the type commonly used with RO (Reverse Osmosis) purifier or RO water purification systems are disclosed in U.S. Pat. Nos. 4,396,357, 4,610,605, 5,476,367, 5,571,000, 5,615,597, 5,649,812, 5,706,715, 5,791,882 and 5,816,133. An example of a conventional compressing diaphragm pump is shown in FIGS. 1 through 10, and essentially comprises a brushed motor 10 with an output shaft 11, a motor upper chassis 30, a wobble plate with an integral protruding cam-lobed shaft 40, an eccentric roundel mount 50, a pump head body 60, a diaphragm membrane 70, three pumping pistons 80, a piston valvular assembly 90 and a pump head cover 20.
The motor upper chassis 30 includes a bearing 31 through which an output shaft 11 of the motor 10 extends. The motor upper chassis 30 also includes an upper annular rib ring 32 with several fastening bores 33 evenly and circumferentially disposed in a rim of the upper annular rib ring 32
The wobble plate 40 includes a shaft coupling hole 41 through which the corresponding motor output shaft 11 of the motor 10 extends.
The eccentric roundel mount 50 includes a central bearing 51 at the bottom thereof for receiving the corresponding wobble plate 40. Three tubular eccentric roundels 52 are evenly and circumferentially disposed on the eccentric roundel mount 50. Each tubular eccentric roundel 52 has a horizontal top face 53, a female-threaded bore 54 and an annular positioning groove 55 formed in the top face thereof, as well as a rounded shoulder 57 created at the intersection of the horizontal top face 53 and a vertical flank 56.
The pump head body 60 covers the upper annular rib ring 32 of the motor upper chassis 30 to encompass the wobble plate 40 and eccentric roundel mount 50 therein, and includes three operating holes 61 evenly and circumferentially disposed therein. Each operating hole 61 has an inner diameter that is slightly bigger than the outer diameter of the corresponding tubular eccentric roundel 52 in the eccentric roundel mount 50 for receiving each corresponding tubular eccentric roundel 52 respectively, a lower annular flange 62 formed thereunder for mating with corresponding upper annular rib ring 32 of the motor upper chassis 30, and several fastening bores 63 evenly disposed around a circumference of the pump head body 60.
The diaphragm membrane 70, which is extrusion-molded from a semi-rigid elastic material and placed on the pump head body 60, includes a pair of parallel rims, including outer raised rim 71 and inner raised rim 72, as well as three evenly spaced radial raised partition ribs 73 such that each end of radial raised partition ribs 73 connects with the inner raised rim 72, thereby forming three equivalent piston acting zones 74 within and partitioned by the radial raised partition ribs 73, wherein each piston acting zone 74 has an acting zone hole 75 created therein in correspondence with a respective female-threaded bore 54 in the tubular eccentric roundel 52 of the eccentric roundel mount 50, and an annular positioning protrusion 76 for each acting zone hole 75 is formed at the bottom side of the diaphragm membrane 70 (as shown in FIGS. 9 and 10).
Each pumping piston 80, which is respectively disposed in each corresponding piston acting zones 74 of the diaphragm membrane 70, has a tiered hole 81 extending therethrough. After each of the annular positioning protrusions 76 in the diaphragm membrane 70 have been inserted into a corresponding annular positioning dent 55 in the tubular eccentric roundel 52 of the eccentric roundel mount 50, respective fastening screws 1 are inserted through the tiered hole 81 of each pumping piston 80 and the acting zone hole 75 of each corresponding piston acting zone 74 in the diaphragm membrane 70, so that the diaphragm membrane 70 and three pumping pistons 80 can be securely screwed into female-threaded bores 54 of the corresponding three tubular eccentric roundels 52 in the eccentric roundel mount 50 (as can be seen in the enlarged portion of FIG. 11).
Piston valvular assembly 90 covers the diaphragm membrane 70 and includes a downwardly extending raised rim 91 for insertion into the gap ring between the outer raised rim 71 and inner raised rim 72 in the diaphragm membrane 70, a central dish-shaped round outlet mount 92 having a central positioning bore 93 with three equivalent sectors, each of which contains multiple evenly circumferentially-located outlet ports 95, a T-shaped plastic anti-backflow valve 94 with a central positioning shank, and three circumferentially-adjacent inlet mounts 96. Each of the circumferentially-adjacent inlet mounts 96 includes multiple evenly circumferentially-located inlet ports 97 and an inverted central piston disk 98 respectively so that each piston disk 98 serves as a valve for each corresponding group of multiple inlet ports 97. The central positioning shank of the plastic anti-backflow valve 94 mates with the central positioning bore 93 of the central outlet mount 92 such that multiple outlet ports 95 in the central round outlet mount 92 are in communication with the three inlet mounts 96, and a hermetically sealed preliminary-compression chamber 26 is formed between each inlet mount 96 and a corresponding piston acting zone 74 in the diaphragm membrane 70 upon insertion of the downwardly extending raised rim 91 into the gap ring between the outer raised rim 71 and inner raised rim 72 of diaphragm membrane 70, such that one end of each preliminary-compressing chamber 26 is in communication with each of the corresponding inlet ports 97 (as shown in the enlarged portion of FIG. 11).
The pump head cover 20, which covers the pump head body 60 to encompass the piston valvular assembly 90, pumping piston 80 and diaphragm membrane 70 therein, includes a water inlet orifice 21, a water outlet orifice 22, and several fastening bores 23. A tiered rim 24 and an annular rib ring 25 are disposed in the bottom inside of the pump head cover 20 such that the outer rim for the assembly of diaphragm membrane 70 and piston valvular assembly 90 can be hermetically attached to the tiered rim 24 (as shown in the enlarged portion of FIG. 11). A high-compression chamber 27 is formed between the cavity formed by the inside wall of the annular rib ring 25 and the central outlet mount 92 of the piston valvular assembly 90 when the bottom of the annular rib ring 25 closely covers the rim of the central outlet mount 92 (as shown in FIG. 11).
By running each fastening bolt 2 through a corresponding fastening bore 23 of pump head cover 20 and a corresponding fastening bore 63 in the pump head body 60, and then putting a nut 3 onto each fastening bolt 2 to securely screw the pump head cover 20 to the pump head body 60 via the corresponding fastening bores 33 in the motor upper chassis 30, the whole assembly of the compressing diaphragm pump is finished (as shown in FIGS. 1 and 11).
Please refer to FIGS. 12 and 13, which are illustrative figures for the operation of the conventional compressing diaphragm pump of FIGS. 1-11.
Firstly, when the motor 10 is powered on, the wobble plate 40 is driven to rotate by the motor output shaft 11 so that the three tubular eccentric roundels 52 on the eccentric roundel mount 50 constantly move in a sequential up-and-down reciprocal stroke.
Secondly, in the meantime, the three pumping pistons 80 and three piston acting zones 74 in the diaphragm membrane 70 are sequentially driven by the up-and-down reciprocal stroke of the three tubular eccentric roundels 52 to move in an up-and-down displacement.
Thirdly, when the tubular eccentric roundel 52 moves in a down stroke, causing pumping piston 80 and piston acting zone 74 to be displaced downwardly, the piston disk 98 in the piston valvular assembly 90 is pushed into an open status so that tap water W can flow into the preliminary-compression chamber 26 via water inlet orifice 21 in the pump head cover 20 and inlet ports 97 in the piston valvular assembly 90 (as indicated by the arrowhead extending from W in the enlarged view of FIG. 12);
Fourthly, when the tubular eccentric roundel 52 moves in an up stroke, causing pumping piston 80 and piston acting zone 74 to be displaced upwardly, the piston disk 96 in the piston valvular assembly 90 is pulled into a closed status to compress the tap water W in the preliminary-compression chamber 26 and increase the water pressure therein up to a range of 80 psi-100 psi. The resulting pressurized water Wp causes the plastic anti-backflow valve 94 in the piston valvular assembly 90 to be pushed to an open status.
Fifthly, when the plastic anti-backflow valve 94 in the piston valvular assembly 90 is pushed to an open status, the pressurized water Wp in the preliminary-compression chamber 26 is directed into high-compression chamber 27 via the group of outlet ports 95 for the corresponding sector in the central outlet mount 92, and then expelled out of the water outlet orifice 22 in the pump head cover 20 (as indicated by arrowhead W in the enlarged portion of FIG. 13).
Finally, the sequential iterative action for each group of outlet ports 95 for the three sectors in central outlet mount 92 causes the pressurized water Wp to be constantly discharged out of the conventional compressing diaphragm pump to be further RO-filtered by the RO-cartridge so that the final filtered pressurized water Wp can be used in the reverse osmosis water purification system.
Referring to FIGS. 14 through 16, a serious vibration-related drawback has long existed in the conventional compressing diaphragm pump. As described previously, when the motor 10 is powered on, the wobble plate 40 is driven to rotate by the motor output shaft 11 so that the three tubular eccentric roundels 52 on the eccentric roundel mount 50 constantly move in a sequential up-and-down reciprocal stroke, while in the meantime three pumping pistons 80 and three piston acting zones 74 in the diaphragm membrane 70 are sequentially driven by the up-and-down reciprocal stroke of the three tubular eccentric roundels 52 to undergo up-and-down displacement so that an equivalent force F constantly acts on the three piston acting zones 74 with a length of moment arm L1 measured from the outer raised rim 71 to the periphery of the annular positioning protrusion 76 (as shown in FIG. 15). Thereby, a resultant torque is created by the acting force F multiplying the length of moment arm L1 according to the formula “torque=acting force F×length of moment arm L1.” The resultant torque causes the whole conventional compressing diaphragm pump to vibrate directly. With a high rotational speed of the motor output shaft 11 in the motor 10 up to a range of 700-1200 rpm, the vibrating strength caused by the alternately acting of three tubular eccentric roundels 52 can reach a persistently unacceptable condition.
To address the drawbacks of the conventional compressing diaphragm pump, as shown in FIG. 16, a cushion base 100 with a pair of wing plates 101 is always provided as a supplemental support, with each wing plate 101 being further sleeved by a rubber shock absorber 102 for enhancing vibration suppression. Upon installation of the conventional compressing diaphragm pump, the cushion base 100 is firmly screwed onto the housing C of the reverse osmosis purification unit by means of suitable fastening screws 103 and corresponding nuts 104. However, the practical vibration suppressing efficiency of the cushion base 100 with wing plates 101 and rubber shock absorber 102 only reduces noise caused by the primary vibration without affect noise caused by secondary vibrations that occur as a result of resonant shaking of the housing C. The secondary vibration actually cause the overall vibration noise of the housing C for the reverse osmosis purification unit to increase.
In addition to drawback of increasing overall vibration noise of the housing C, a further drawback occurs in that the water pipe P connected to the water outlet orifice 22 of the pump head cover 20 will synchronously shake in resonance with the vibrations described above (as indicated by the broken line depictions of water pipe P in FIGS. 16 and 16a). This synchronous shaking of the water pipe P will result in still further drawbacks by causing other parts of the conventional compressing diaphragm pump to simultaneously shake. As a result, after a certain period, the water leakage of the conventional compressing diaphragm pump will occur due to gradual loosening of the connection between water pipe P and water outlet orifice 22, as well as gradual loosening of the fit between other parts affected by the shaking. The additional drawbacks of overall resonant shaking and water leakage in the conventional compressing diaphragm pump cannot be resolved by the above-described conventional way of addressing primary vibrations using a shock-absorbing cushion base 100. Therefore, how to substantially reduce all of the drawbacks associated with the operating vibration for the compressing diaphragm pump has become an urgent and critical issue.
FIGS. 17 and 18 illustrate yet another problem with the conventional compressing diaphragm pump. As described previously, when the motor 10 is powered on, the wobble plate 40 is driven to rotate by the motor output shaft 11 so that three tubular eccentric roundels 52 on the eccentric roundel mount 50 constantly move in a sequential up-and-down reciprocal stroke, and the three piston acting zones 74 in the diaphragm membrane 70 are sequentially driven by the up-and-down reciprocal stroke of the three tubular eccentric roundels 52 to move in up-and-down displacement so that a force F constantly acts on the bottom side of each piston acting zone 74.
Meanwhile a corresponding plurality of rebounding forces Fs are created in reaction to the acting force F exerted on the bottom side of diaphragm membrane 70, with different components distributed over the entire bottom area of each corresponding piston acting zone 74 in the diaphragm membrane 70, as shown in FIG. 18, so that a squeezing phenomenon caused by the rebounding forces Fs occurs on a section of the diaphragm membrane 70.
Among all of the distributed components of the rebounding force Fs, the maximum component force is exerted at the contacting bottom position P of the diaphragm membrane 70 with the rounded shoulder 57 of the horizontal top face 53 in the tubular eccentric roundel 52 so that the squeezing phenomenon at the bottom position P is also maximum, as shown in FIG. 18.
With the rotational speed for the motor output shaft 11 of the motor 10 reaching a range of 700-1200 rpm, each bottom position P of the piston acting zone 74 of the diaphragm membrane 70 suffers from the squeezing phenomenon at a frequency of four times per second. Under such circumstances, the bottom position P of the diaphragm membrane 70 is always the first broken place for the entire conventional compressing diaphragm pump, which is an essential cause of not only shortening the service lifespan but also terminating the normal function of the conventional compressing diaphragm pump.
Therefore, how to substantially reduce the drawbacks associated with the squeezing phenomenon caused by the constant application of force F to the bottom side of each piston acting zone 74 of the diaphragm membrane 70 as a result of the movement of the tubular eccentric roundel 52 has also become an urgent and critical issue.